Method of manufacturing a gas discharge panel

ABSTRACT

A gas discharge panel in which the conductors of the base plate and the upper plate are connected to said base plate and upper plate by means of an enamel.

p 1974 J. VAN ESDONK ETAL 3,837,958

METHOD OF MANUFACTURING A GAS DISCHARGE PANEL Filed June 22, 1972.

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United States Patent US. Cl. 156-229 7 Claims ABSTRACT OF THE DISCLOSUREA gas discharge panel in which the conductors of the base plate and theupper plate are connected to said base plate and upper plate by means ofan enamel.

The invention relates to a method of manufacturing a gas dischargepicture display panel consisting at least of a base plate and an upperplate which consists of a light-pervious material, the base plate andthe upper plate being provided with mutually insulated conductors, anumber of cavities being present between the conductors of the baseplate and the upper plate in which cavities gas discharges can occurwhen suitable potential differences are applied between the conductors.The invention furthermore relates to a gas discharge panel manufacturedby said method.

The connection of a large number of generally parallel strip-likeconductors to the base plate and/or the upper plate is not simple.

It is known to provide said conductors in grooves of an electrolyticallyoxidized aluminum plate, but this method is laborious. The conductorscan be clamped in the correct position and be provided on the base plateof a mold, after which melted glass is poured over the conductors sothat the latter are embedded in a glass plate, but it has been foundthat glass can flow between the base plate and the conductors as aresult of which the effective surface of the conductors is covered withglass. Cleaning of said effective surface is very time-consuming.Pressing the conductors in a softened glass plate can also presentdifiiculties as a result of a mutual displacement or deformation of theconductors. In addition, the glass plate becomes less bright as a resultof the strong heating.

A comparatively simple method of manufacturing gas discharge panels isobtained if, according to the invention, the conductors which areprovided in the mutually correct position are secured to the base plateand/or the upper plate by means of a readily melting type of glass(enamel). The conductors can be covered on one side with a layer ofenamel suspension and be laid with said side on a base plate or upperplate, after which the enamel is melted so that the conductors aresecured to the plate.

The thickness of the conductors causes a number of channels to be formedwhich interconnect the cavities to be provided between the base plateand the upper plate.

In order to avoid undesirable discharges between the edges of theconductors facing each other, said edges may also be covered withenamel. This can be achieved in a simple manner if the enamel suspensionis provided on the base plate and/or the upper plate and is melted,after which the conductors are pressed into the soft enamel. By suitablechoice of the thickness of the layer of enamel suspension in relation tothe thickness of the conductors and the mutual distance of theconductors, it can be achieved that the enamel covers the side edges ofthe conductors without the channels formed between the conductorsbecoming too narrow. During pressing the conductors into the enamel theyare preferably also stretched.

A large number of conductors can be fixed with their ends in the correctposition, but an assembly of conductors is preferably formed byphotochemically etching slots in a metal plate. The pattern of theconductors or of the slots can be provided in the correct position inknown manner photographically. The laborious provision at determinedmutual distances and fixing of separate conductors is then superfluous.

The invention will be described in greater detail with reference to theaccompanying drawing in which FIG. 1 is a sectional view of a part of apanel according to the invention, while FIGS. 2, 4 and 6 show otherembodiments of a plate with conductors according to the invention, and

FIGS. 3, 5 and 7 are the corresponding cross-sectional views of FIGS. 2,4 and 6.

In FIG. 1, 1 is a base plate, 2 a light-pervious upper plate and 3 is aperforated intermediate plate. The base plate 1 comprises a number ofparallel strip-like conductors 4 and the upper plate 2 comprises anumber of parallel conductors 5 extending at right angles to thedirection of the conductors 4. The apertures 7 of the plate 3 arelocated exactly at the intersections of the conductors 4 and 5 and arefilled with a suitable gas with a given pressure.

The conductors 4 are secured to the base plate 1 by means of enamel 6,the conductors 5 are secured to the upper plate 2. The spaces 8 betweenthe conductors 4 and 5 communicate with all the cavities and enable theevaporation of the cavities 7 and the provision of the gas filling insaid cavities 7. The channels formed by the spaces 8 open into a commonduct, not shown, which is provided with an exhaust tube.

The conductors 4 and 5, respectively, are preferably formed by etchingslots in a metal plate. The ends of the conductors 4 and 5,respectively, are then connected together by means of a rectangleconsisting of four fillets. The conductors are coated on one side withan enamel suspension 5 and laid with this side on the base plate 1 andthe upper plate 2, respectively. The fillets extending parallel to theconductors are removed, the fillets extending at right angles to theconductors being drawn apart by means of a drawing device, for examplesprings, so as to stretch the conductors. By melting the enamelsuspension the conductors are then connected to the plates 1 and 2,respectively, and the fillets are removed. The plates 1, 2 and 3 withthe conductors 4 and 5 are then placed one on the other and a suspensionof sealing glass is provided near the edges of the plates 1, 2 and 3.The

assembly is placed in a furnace and heated so that the sealing glassjoins the plates 1, 2 and 3 together in a vacuum-tight manner. Byremoving the fillets, the conductors are insulated from each other. Thecavities 7 are then evacuated through the ducts 8 and the desirable gasis introduced into the cavities 7.

There often exists the danger of discharges between the oppositelylocated edges of the conductors 4 and 5, respectively. In order to avoidthis, said edges may be covered with enamel.

This is preferably done by means of the method according to FIGS. 2 and3. For that purpose, the suspension of the enamel 6 is provided on theplate 1 or 2 and the conductors 4 and 5, respectively, are pressed intothe enamel after having heated and melted this. The enamel pressed awayby the conductors 4 and 5, respectively, will enter into the ducts 8between the conductors and cover the side edges of the conductors as aresult of the surface tension. In order to prevent the channels frombecoming too narrow, the thickness of the layer of enamel must generallybe less than 25% of the thickness of the conductors. In a favourableembodiment the thickness of the enamel layer was 20 that of theconductors 100g. The width of the cathode conductors on the base plateis 0.5 mm., that of the anode conductors on the upper plate is 150 Thecenter distance of cathode and anode conductors is the same, namely 1.2-mm. However, it is also possible to cover the side edges with enamelsuspension simultaneously with the provision of the one-sided layer.However, this is not so simple as the above-mentioned method since thepossibility exists that the suspension will reach the effective surfaceof the electrodes.

If it is desirable to incorporate a memory in the tube, the conductors 5may be fully covered with a semi-conductive layer. The strip-likeconductors 5 are then preferably replaced by the filamentary conductors9 (FIGS. 6 and 7) which are covered with a semiconductive enamel layer10. This enamel may also serve for the adhesion of the wires 9 to theplate 2. The wires 9 consist, for example, of chromium iron and have adiameter of 0.1 mm., the enamel layer 10 being 40p thick.

The conductors 4 and 5 are preferably manufactured by photochemicallyetching slots in a chromium-nickeliron sheet, 0.1 mm. thick. Theadditional advantage of the use of enamel for securing the conductors tobase plate and upper plate is that said plates which usually consist ofglass remain fully bright.

Since the conductors are heated to a lower temperature than uponpressing in a molten glass plate, the possibility of oxidation of theeffective surface of the conductors is smaller, while discoloring of theglass plate as a result of dissolving oxide of the conductors does notoccur. The plates may advantageously consist of window glass.

What is claimed is:

1. In the method of manufacturing a gas discharge picture display panelcomprising a base plate and a lightpervious upper plate, the base plateand the upper plate comprising a number of mutually insulatedconductors, a number of cavities in which gas discharge can occur whensuitable potential differences are set up between the conductors beingpresent between the conductors of the base plate and the upper plate,the step of securing the conductors provided in the correct position tothe base plate and the upper plate with a readily melting enamel.

2. A method as claimed in Claim 1, wherein the conductors are coated onone side with an enamel suspension and are connected with the coatedside to a base plate and upper plate by melting the enamel suspension.

3. A method as claimed in Claim 2, wherein the side edges of theconductors facing each other are also covered with enamel suspension.

4. A method as claimed in Claim 1, wherein a layer of an enamelsuspension is provided on a base plate and upper plate and is heated tomelt the enamel and thereafter pressing the conductors in the softenedenamel layer, the enamel also covering the edges of the conductorsfacing each other.

5. A method as claimed in Claim 1 wherein the conductors are stretchedduring the securing by means of enamel.

6. A method as claimed in Claim 1 wherein the conductors are partlycovered with an enamel suspension, and thereafter heating the enamelsuspension to melt the same and secure the conductors to the upper andbase plate respectively.

7. A method as claimed in Claim 1 wherein the base and upper plates arepartly covered with an enamel suspension, the conductors are positionedon the base and upper plates respectively and thereafter heating theenamel suspension to melt the same and secure the conductors to saidbase and upper plates, respectively.

References Cited UNITED STATES PATENTS 3,603,837 9/1971 Turner 313218 X3,697,793 10/1972 King 313-217 X 3,735,183 5/1973 Walters 313217 XWILLIAM A. POWELL, Primary Examiner B. J. LEITTEN, Assistant ExaminerUS. Cl. X.R.

